资讯专栏INFORMATION COLUMN

[LeetCode] 429. N-ary Tree Level Order Traversal (

LiangJ / 2606人阅读

429. N-ary Tree Level Order Traversal

Given an n-ary tree, return the level order traversal of its nodes" values. (ie, from left to right, level by level).

For example, given a 3-ary tree:

We should return its level order traversal:

[
     [1],
     [3,2,4],
     [5,6]
]    

Note:

The depth of the tree is at most 1000.
The total number of nodes is at most 5000.

Solution (Iteration)

use Queue, in each level, use queue.size() to loop

class Solution {
    public List> levelOrder(Node root) {
        List> res = new ArrayList<>();
        if (root == null) return res;
        Queue queue = new LinkedList<>();
        queue.offer(root);
        while (!queue.isEmpty()) {
            List curRes = new ArrayList<>();
            int size = queue.size();
            for (int i = 0; i < size; i++) {
                Node node = queue.poll();
                curRes.add(node.val);
                for (Node child: node.children) {
                    queue.offer(child);
                }
            }
            res.add(curRes);
        }
        return res;
    }
}
102. Binary Tree Level Order Traversal

Given a binary tree, return the level order traversal of its nodes" values. (ie, from left to right, level by level).

For example:
Given binary tree [3,9,20,null,null,15,7],

    3
   / 
  9  20
    /  
   15   7

return its level order traversal as:

[
  [3],
  [9,20],
  [15,7]
]
Solution (Iteration)
class Solution {
    public List> levelOrder(TreeNode root) {
        List> res = new ArrayList<>();
        if (root == null) return res;
        Queue queue = new LinkedList<>();
        queue.offer(root);
        while (!queue.isEmpty()) {
            List curRes = new ArrayList<>();
            int size = queue.size();
            for (int i = 0; i < size; i++) {
                TreeNode node = queue.poll();
                curRes.add(node.val);
                if (node.left != null) queue.offer(node.left);
                if (node.right != null) queue.offer(node.right);
            }
            res.add(curRes);
        }
        return res;
    }
}

文章版权归作者所有,未经允许请勿转载,若此文章存在违规行为,您可以联系管理员删除。

转载请注明本文地址:https://www.ucloud.cn/yun/77375.html

相关文章

  • leetcode429. N-ary Tree Level Order Traversal

    摘要:题目要求对叉树进行水平遍历,并输出每一行遍历的结果。因此无需再用队列来额外存储每一行的水平遍历,可以直接通过递归将遍历结果插入到相应行的结果集中。 题目要求 Given an n-ary tree, return the level order traversal of its nodes values. (ie, from left to right, level by level)...

    tomlingtm 评论0 收藏0
  • Leetcode PHP题解--D55 429. N-ary Tree Level Order Tr

    摘要:题目链接题目分析按层遍历叉树。思路以层数为键,塞入当前节点的值。最终代码若觉得本文章对你有用,欢迎用爱发电资助。 D55 429. N-ary Tree Level Order Traversal 题目链接 429. N-ary Tree Level Order Traversal 题目分析 按层遍历N叉树。 思路 以层数为键,塞入当前节点的值。 递归遍历即可。 最终代码

    libxd 评论0 收藏0
  • [LeetCode] 590. N-ary Tree Postorder Traversal (vs

    摘要:按顺序放入,正好方面是从到,顺序方面是从最右到最左,因为是先入后出。这样最后一下就是先左后右,先子后根。 590. N-ary Tree Postorder Traversal Problem Given an n-ary tree, return the postorder traversal of its nodes values.For example, given a 3-ar...

    sydMobile 评论0 收藏0
  • [LeetCode] 589. N-ary Tree Preorder Traversal (vs.

    589. N-ary Tree Preorder Traversal Given an n-ary tree, return the preorder traversal of its nodes values.For example, given a 3-ary tree:showImg(https://segmentfault.com/img/bVbhKkv?w=781&h=502);Retu...

    array_huang 评论0 收藏0
  • Leetcode PHP题解--D43 589. N-ary Tree Preorder Trave

    摘要:题目链接题目分析维数组的先序遍历。这题也不想多说什么了。是比较基础的题目了。先序就是先根后子而已。思路在遍历子节点之前,先保存当前节点的信息。最终代码若觉得本文章对你有用,欢迎用爱发电资助。 D43 589. N-ary Tree Preorder Traversal 题目链接 589. N-ary Tree Preorder Traversal 题目分析 N维数组的先序遍历。 这题也...

    junbaor 评论0 收藏0

发表评论

0条评论

最新活动
阅读需要支付1元查看
<